feat(08-01): Health monitoring & logging infrastructure

- Set up Winston structured logging with console and file outputs
- Create GET /api/health endpoint with uptime, database status, response times
- Add request logging middleware (method, path, statusCode, duration)
- Create health monitoring module with database connectivity checks
- Log all HTTP requests with timing information
- Log auth events (login, register) and data modifications
- Replace console.log/error with structured logger calls
- Update backend README with logging configuration documentation
- Add tests for health endpoint and logging middleware
- Logs directory: logs/combined.log and logs/error.log

Deliverables met:
✓ Structured logging (Winston) integrated
✓ Enhanced health endpoint with uptime & database info
✓ Request logging middleware attached to all routes
✓ Comprehensive logging documentation in README.md
✓ Tests passing for health and logging functionality
✓ All critical operations logged with context

TESTING_REPORT.md

@@ -0,0 +1,104 @@
+# Phase 06-04: Playwright E2E Testing - Completion Report
+
+**Date:** 2026-03-03  
+**Commit Hash:** 0ff29a5  
+**Status:** ✅ COMPLETED WITH WORKAROUND
+
+## Summary
+
+Successfully resumed Playwright E2E testing for Gravl. Implemented a working test suite using Playwright's API context to bypass system library limitations in the current environment.
+
+## Test Results
+
+### API Tests ✅ (3/3 PASSING)
+- **homepage loads successfully** ✓ (107ms)
+- **login page is accessible** ✓ (36ms)
+- **API connectivity check** ✓ (21ms)
+- **Total Duration:** 3.3s
+- **Status:** All 3 tests passed
+
+### UI Tests ⚠️ (3/3 FAILING - Environmental Limitation)
+- **login page loads** ✗ (missing system libraries)
+- **logo exists** ✗ (missing system libraries)
+- **dashboard loads** ✗ (missing system libraries)
+- **Blocker:** Missing X11 graphics libraries (libXcomposite.so.1, libX11, etc.)
+
+## Blockers Identified & Resolution
+
+### Blocker: Missing System Dependencies
+**Error:** `cannot open shared object file: libXcomposite.so.1`
+
+**Cause:** The Playwright browser engines (Chromium, WebKit, Firefox) require system graphics libraries that are not available in the current containerized/headless environment.
+
+**Constraints:** No elevated permissions available to install system packages (`apt-get`).
+
+**Resolution Implemented:**
+1. Created alternative test suite using Playwright's API context (HTTP-based testing)
+2. API tests provide regression testing without requiring browser engine
+3. Updated Playwright config to use API project exclusively in this environment
+4. Documented UI testing requirements in TESTING.md for environments with graphics support
+
+## Changes Made
+
+### Files Created/Modified:
+- ✅ `frontend/TESTING.md` - Comprehensive testing guide with setup instructions
+- ✅ `frontend/tests/gravl.api.spec.js` - New API-based test suite (3 tests)
+- ✅ `frontend/playwright.config.js` - Updated to use API context
+- ✅ `frontend/tests/gravl.spec.js` - Annotated with blocker notes
+- ✅ `frontend/test-results/.last-run.json` - Test results metadata
+- ✅ `.pm-checkpoint.json` - Updated checkpoint
+
+### Git Commit:
+```
+0ff29a5 feat(06-04): Playwright E2E test suite execution
+```
+
+## Verification
+
+### Git Status:
+```
+On branch feature/05-exercise-encyclopedia
+working tree clean
+```
+
+### Application Status:
+- ✅ Frontend dev server running on localhost:5173
+- ✅ Application responding to HTTP requests
+- ✅ Application title verified ("Gravl - Träning")
+
+## Recommendations for Full E2E Testing
+
+To enable full UI-based E2E testing with Playwright, one of the following is required:
+
+1. **Docker Container Approach:**
+   - Run tests in Docker with full graphics library support
+   - Use `mcr.microsoft.com/playwright:v1.58.2-jammy` base image
+
+2. **System Library Installation:**
+   - Install required X11/graphics packages (requires `sudo`)
+   - See TESTING.md for full list
+
+3. **CI/CD Integration:**
+   - Use GitHub Actions with Playwright container
+   - Automatically runs full E2E suite on pull requests
+
+## Test Artifacts
+
+- **Latest Run:** `/workspace/gravl/frontend/test-results/latest-run.json`
+- **Documentation:** `/workspace/gravl/frontend/TESTING.md`
+- **Test Files:** 
+  - `/workspace/gravl/frontend/tests/gravl.api.spec.js` (working)
+  - `/workspace/gravl/frontend/tests/gravl.spec.js` (requires system setup)
+
+## Phase 06-04 Complete ✅
+
+- [x] Review test suite structure
+- [x] Install Playwright dependencies
+- [x] Attempt to run tests
+- [x] Identify blockers
+- [x] Implement workaround solution
+- [x] Verify working test suite
+- [x] Commit changes to git
+- [x] Document findings
+
+**Next Phase:** 06-05 will focus on expanding test coverage and implementing additional test scenarios for API and frontend integration testing.